Re: [Intel-gfx] [PATCH v5 0/5] Use drm_clflush* instead of clflush

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 07 Feb 2022, Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> wrote:
> On 04/02/2022 16:37, Michael Cheng wrote:
>> This patch series re-work a few i915 functions to use drm_clflush_virt_range
>> instead of calling clflush or clflushopt directly. This will prevent errors
>> when building for non-x86 architectures.
>> 
>> v2: s/PAGE_SIZE/sizeof(value) for Re-work intel_write_status_page and added
>> more patches to convert additional clflush/clflushopt to use drm_clflush*.
>> (Michael Cheng)
>> 
>> v3: Drop invalidate_csb_entries and directly invoke drm_clflush_virt_ran
>> 
>> v4: Remove extra memory barriers
>> 
>> v5: s/cache_clflush_range/drm_clflush_virt_range
>
> Is anyone interested in this story noticing my open? I will repeat:
>
> How about we add i915_clflush_virt_range as static inline and by doing 
> so avoid adding function calls to code paths which are impossible on Arm 
> builds? Case in point relocations, probably execlists backend as well.
>
> Downside would be effectively duplicating drm_clfush_virt_range code. 
> But for me, (Also considering no other driver calls it so why it is 
> there? Should it be deleted?), that would be okay.

Keep it simple first, optimize later if necessary?

BR,
Jani.


>
> Regards,
>
> Tvrtko
>
>> Michael Cheng (5):
>>    drm/i915/gt: Re-work intel_write_status_page
>>    drm/i915/gt: Drop invalidate_csb_entries
>>    drm/i915/gt: Re-work reset_csb
>>    drm/i915/: Re-work clflush_write32
>>    drm/i915/gt: replace cache_clflush_range
>> 
>>   .../gpu/drm/i915/gem/i915_gem_execbuffer.c    |  8 +++-----
>>   drivers/gpu/drm/i915/gt/gen8_ppgtt.c          | 12 ++++++------
>>   drivers/gpu/drm/i915/gt/intel_engine.h        | 13 ++++---------
>>   .../drm/i915/gt/intel_execlists_submission.c  | 19 ++++++-------------
>>   drivers/gpu/drm/i915/gt/intel_gtt.c           |  2 +-
>>   drivers/gpu/drm/i915/gt/intel_ppgtt.c         |  2 +-
>>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c |  2 +-
>>   7 files changed, 22 insertions(+), 36 deletions(-)
>> 

-- 
Jani Nikula, Intel Open Source Graphics Center